[processing] fix batch input selection panel for multiple layers parameter

Author: nirvn

python/plugins/processing/gui/BatchInputSelectionPanel.py

@@ -85,7 +85,7 @@ def showPopupMenu(self):
         popupmenu = QMenu()
 
         if not (isinstance(self.param, QgsProcessingParameterMultipleLayers) and
-                self.param.datatype == dataobjects.TYPE_FILE):
+                self.param.layerType == dataobjects.TYPE_FILE):
             selectLayerAction = QAction(
                 self.tr('Select from open layers'), self.pushButton)
             selectLayerAction.triggered.connect(self.showLayerSelectionDialog)